Spectrum Pharmaceuticals Announces Belinostat Data Presentation at 101st Annual Meeting of the American Association for Cancer Research

Data Suggest HDAC Inhibitors,
Such as Belinostat, May Be Efficacious in the Treatment of Small
Cell Lung Cancer

Results Indicate Synergy With
Conventional Chemotherapy Agents

IRVINE, Calif.--(BUSINESS WIRE)--Apr 21, 2010 - Spectrum
Pharmaceuticals, Inc. (NasdaqGM:SPPI), a commercial-stage
biotechnology company with a primary focus in oncology, today
announced results of a pre-clinical study conducted by the National
Cancer Institute of belinostat in the treatment of small-cell lung
cancer that was presented in a poster session on Wednesday, April
21, 2010 at the 101st Annual Meeting of the American Association
for Cancer Research (AACR), being held at the Walter E. Washington
Convention Center in Washington, DC.

“Based on the data presented today at AACR, we believe
belinostat may be an effective treatment option for small-cell lung
cancer,” said Rajesh C. Shrotriya, MD, Chairman, President
and Chief Executive Officer of Spectrum Pharmaceuticals, Inc.
“While we continue to enroll patients into the 100-evaluable
patient registrational trial for belinostat in peripheral T-cell
lymphoma (PTCL), being conducted under a Special Protocol
Assessment by the FDA, we are exploring potential clinical trial
design options for the treatment of lung cancer.”

Small Cell Lung Cancer (SCLC) is the most aggressive type of
lung carcinoma. SCLC has a high response rate to chemotherapy, but
rapid onset of drug resistance. Chemotherapeutic treatment using
combinations of drugs that target different signaling pathways have
demonstrated improvement in overall survival of patients with SCLC.
HDAC inhibitors play a role in regulating cell cycle progression
and have been suggested as potential therapeutic agents for SCLC.
HDAC inhibition is believed to relax DNA, thereby allowing
increased access of transcription factors to certain promoters.
Likewise, these agents could increase accessibility of DNA to
cytotoxic agents.

Two distinct HDAC inhibitors, belinostat and depsipeptide, were
examined to determine whether they have an effect on SCLC lines and
whether they could be combined with conventional chemotherapy
agents etoposide and cisplatin for SCLC.

Simultaneous and schedule-depended treatment protocols of SCLC
cells with single drugs and drug combinations were used.
Computational analysis of cell survival using combination index
(CI) showed that HDAC inhibitors synergized with DNA damaging
agents when administered simultaneously, but this effect was only
additive if cells were pre-treated with HDAC inhibitors for 24
hours prior to DNA damaging agents. In addition, using DNA damaging
agents 24 hours prior to HDAC inhibitors was clearly antagonistic
with CI>1 for all drugs and cell lines tested.

Because of a potential use of belinostat and depsipeptide for
therapy of SCLC in combination with conventional chemotherapies,
the mechanisms of synergy and protection between these agents were
examined. PolyADP-ribose polymerase (PARP) degradation was complete
when drugs were used simultaneously, but was decreased if HDAC
inhibitors were used prior to cisplatin or etoposide. The
degradation of PARP enzyme prevents repair of DNA strand breaks
caused by chemotherapeutic agents and thereby facilitates the
programmed cell death, or apoptosis, of cancer cells. Therefore, a
greater degree of PARP degradation is indicative of a greater
capacity of a given anti-cancer agent or a combination of agents to
induce apoptosis.

It was concluded that HDAC inhibitors synergize with DNA
damaging agents only if administered simultaneously. Treatment of
cells with HDAC inhibitors and DNA damaging agents induces PARP
degradation. Combination of HDAC inhibitors with etoposide does not
affect single stranded DNA damage. Simultaneous treatment with DNA
damaging agents increases double strand DNA damage. The design of
clinical trials for combination of HDAC inhibitors and
chemotherapeutic agents should take into account the timing that
induces maximum effect.

About Belinostat

Belinostat (PXD 101) is a Class I and II HDAC inhibitor that is
being studied in multiple clinical trials as a single agent or in
combination with chemotherapeutic agents for the treatment of
various hematological and solid cancers. Its anticancer effect is
thought to be mediated through multiple mechanisms of action,
including the inhibition of cell proliferation, induction of
apoptosis (programmed cell death), inhibition of angiogenesis,
induction of differentiation, and the resensitization of cells that
have overcome drug resistance to anticancer agents such as
platinums, taxanes and topoisomerase II inhibitors. Belinostat is
the only HDAC inhibitor in clinical development with multiple
potential routes of administration, including intravenous
administration, continuous intravenous infusion and oral
administration.

Belinostat is currently in a registrational trial, under a
Special Protocol Assessment (SPA), as a monotherapy for relapsed or
refractory Peripheral T-Cell Lymphoma (PTCL), an indication for
which it has been granted Orphan Drug and Fast Track designation by
the U.S. Food and Drug Administration. The Company currently plans
to file a New Drug Application (NDA) in 2011. Belinostat is also
under investigation in a randomized Phase 2 trial, as a combination
therapy with carboplatin and paclitaxel, for cancer of unknown
primary (CUP). Additionally, the National Cancer Institute is
currently conducting several clinical trials of Belinostat in a
variety of hematological and solid tumors, both as monotherapy as
well as combination therapy.

About Spectrum Pharmaceuticals

Spectrum Pharmaceuticals is a commercial-stage biotechnology
company with a focus in hematology and oncology. The Company's
strategy is comprised of acquiring, developing and commercializing
a broad and diverse pipeline of late-stage clinical and commercial
products. In addition to building an efficient in-house clinical
research organization with regulatory and data management
capabilities, the Company has established a commercial
infrastructure for its drug portfolio. The Company markets two
oncology drugs, FUSILEV and ZEVALIN and has two drugs in late stage
development, apaziquone and belinostat, along with a diverse
pipeline. The Company also leverages the expertise of its worldwide
partners to assist in the execution of its strategy. For more
information, please visit the Company's website at www.sppirx.com.

Forward-looking statement – This press release may
contain forward-looking statements regarding future events and the
future performance of Spectrum Pharmaceuticals that involve risks
and uncertainties that could cause actual results to differ
materially. These statements include but are not limited to
statements that relate to Spectrum's ability to identify, acquire,
develop and commercialize a broad and diverse pipeline of
late-stage clinical and commercial products, establishing a
commercial organization for our approved drugs, continuing to build
our team, leveraging the expertise of partners around the world to
assist us in the execution of our strategy, the safety and efficacy
of belinostat, that belinostat may be efficacious in the treatment
of small cell lung cancer and have synergy with conventional
chemotherapy agents, potential clinical trial design options for
belinostat for the treatment of lung cancer, that belinostat has
multiple potential routes of administration, including intravenous
administration, continuous intravenous infusion and oral
administration, that the Company currently plans to file a New Drug
Application (NDA) in 2011 and any statements that relate to the
intent, belief, plans or expectations of Spectrum or its
management, or that are not a statement of historical fact. Risks
that could cause actual results to differ include the possibility
that our existing and new drug candidates may not prove safe or
effective, the possibility that our existing and new drug
candidates may not receive approval from the FDA, and other
regulatory agencies in a timely manner or at all, the possibility
that our existing and new drug candidates, if approved, may not be
more effective, safer or more cost efficient than competing drugs,
the possibility that our efforts to acquire or in-license and
develop additional drug candidates may fail, our lack of revenues,
our limited marketing experience, our dependence on third parties
for clinical trials, manufacturing, distribution and quality
control and other risks that are described in further detail in the
Company's reports filed with the Securities and Exchange
Commission. We do not plan to update any such forward-looking
statements and expressly disclaim any duty to update the
information contained in this press release except as required by
law.